The NavigableSet API docs state that methods headSet,tailSet(E),headSet(E) and subSet(E, E) return a NavigableSet. In Eclipse, I get a type mismatch error, although I use the 1.6_20 jdk and have my compiler compliance set to 1.6, so I have to "downgrade" the return value to SortedSet. Am I missing something? ...
What I want is basically a collection that's a hybrid of a dictionary and a list. I want a collection that I can add key/value pairs to (like a Dictionary), but at the same be able to retrieve the values (without the keys) in the same order I added them (like a List)? Does such a collection exists in .NET? Thanks ...
Just starting to work with Doctrine2, and am wondering how/if I can use a custom collection class. Searches point me to this part of the documentation: Collection-valued persistent fields and properties must be defined in terms of the Doctrine\Common\Collections\Collection interface. The collection implementation type may be used by ...
For every situation that warrants the use of an array ... there is an awesome collection with benefits. Is there any specific use case for Arrays any more in .NET? ...
I want to create a timesheet application where I need an application that will collect data from the logged in user regarding the number of hours they worked on a specific date. The user will be required to log into an application which will capture their credentials and employee ID. Users will be presented with a form that will list ...
Why do some collection data structures not maintain the order of insertion? What is the special thing achieved compared to maintaining order of insertion? Do we gain something if we don't maintain the order? ...
Hi, I have a class e.g. MyDataClass. I have a HashMap<String,MyDataClass> myMap; For each reference in the myMap, I also have some other MyDataClass references to the same object. To be specific: MyDataClass c = new MyDataClass(); //configure c object with appropriate values myMap.put("akeyvalue",c); MyDataClass ref = c; At this poin...
In my app, I'm working with Simfile and Notechart objects. A Simfile is essentially a Notechart container, with the following constraints: 1) Every Notechart must be contained in exactly one parent Simfile, at all times. 2) Given a Simfile object, I need to be able to obtain all of its contained Notecharts (should be easy). 3) Given a N...
Ok please excuse my references to the gridview. So i have this method in a class called getall() what this does is gets the collection of entites from entity framework model for a specfic table, checks to see whether the table exists and then does the query using linq (linq to entities). This does work as I have used a breakpoint and ev...
According to the documentation on ABCs, I should just have to add a next method to be able to subclass collections.Iterator. So, I'm using the following class: class DummyClass(collections.Iterator): def next(self): return 1 However, I get an error when I try to instantiate it: >>> x = DummyClass() Traceback (most recent...
I have an array list that contains Quote objects. I want to be able to sort alphabetically by name, by change, and by percent change. How can I sort my arraylist? package org.stocktwits.model; import java.io.Serializable; import java.text.DecimalFormat; public class Quote implements Serializable { private static final lon...
I'm tired of this dictionary idiom: Dictionary<Guid,Contact> Contacts; //... if (!Contacts.ContainsKey(id)) { contact = new Contact(); Contacts[id] = contact; } else { contact = Contacts[id]; } It would be nice if there was a syntax tha...
I am trying to sort my ArrayList, but when I check the first item in my supposedly sorted array, it is incorrect. I am not sure why? Am I missing anything? Here is my Comparator: package org.stocktwits.helper; import java.util.Comparator; import org.stocktwits.model.Quote; public class NameComparator implements Comparator<Quote> { ...
why the methods transform (in-place mutation version of map) and retain (in-place mutation version of filter) are defined on only mutable.Map but not on mutable.Buffer and mutable.Set? shouldnt all mutable collections support these methods? ...
Sets and lists are handled differently in Python, and there seems to be no uniform way to work with both. For example, adding an item to a set is done using the add method, and for the list it is done using the append method. I am aware that there are different semantics behind this, but there are also common semantics there, and often a...
I have to filter and to sort a ArrayList wíth objects. - Every object has 2 integer pairs => 4 ints per Object. - Every value of Column_1 < Column_2 and - Every value of Column_3 < Column_4. ... so each pair represents a distance. 1.) Distance in 1st(Column_1,Column_2) pair and 2nd(Column_3, Column_4,) pair have to be equal. 2.) if t...
Given a starting List<Foo>, what is the most concise way to determine if a Foo element having a property bar (accessed by getBar()) has a value of "Baz"? The best answer I can come up with is a linear search: List<Foo> listFoo; for(Foo f:listFoo) { if(f.getBar().equals("Baz")) { // contains value } } I looked into Hash...
In Java, 'Set' and 'List' are interfaces derived from 'Collection' interface. If we use the code: import java.util.*; public class SetExample{ public stactic void main(String[] args){ Set set = new HashSet(); //do something ..... } } Is there a class 'Set' in "Collection" API that we are creating an object ('set...
I am writing a space invaders game I need to write 5 public instance variables which hold collections recording all of the information about one run of the game: spaceShips will reference a list of SpaceShip, in the order they appeared on the screen public List spaceShips; blinks are shots which will reference a list of all instan...
When deciding to use a specific container (List/Set/Map), I like to consider the performance (big-Oh notation) metrics of operations such as insert, delete, get, etc. This is so I can select the best container for my needs. The API docs always specify synchronized/unsynchronized, but not other performance metrics. Is there a table of r...